'\"
'\" Generated from file 'idx_export\&.man' by tcllib/doctools with format 'nroff'
'\" Copyright (c) 2009-2019 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>
'\"
.TH "doctools::idx::export" n 0\&.2\&.1 tcllib "Documentation tools"
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.BS
.SH NAME
doctools::idx::export \- Exporting keyword indices
.SH SYNOPSIS
package require \fBdoctools::idx::export  ?0\&.2\&.1?\fR
.sp
package require \fBTcl  8\&.4\fR
.sp
package require \fBstruct::map \fR
.sp
package require \fBdoctools::idx::structure \fR
.sp
package require \fBsnit \fR
.sp
package require \fBpluginmgr \fR
.sp
\fB::doctools::idx::export\fR \fIobjectName\fR
.sp
\fBobjectName\fR \fBmethod\fR ?\fIarg arg \&.\&.\&.\fR?
.sp
\fIobjectName\fR \fBdestroy\fR
.sp
\fIobjectName\fR \fBexport serial\fR \fIserial\fR ?\fIformat\fR?
.sp
\fIobjectName\fR \fBexport object\fR \fIobject\fR ?\fIformat\fR?
.sp
\fIobjectName\fR \fBconfig names\fR
.sp
\fIobjectName\fR \fBconfig get\fR
.sp
\fIobjectName\fR \fBconfig set\fR \fIname\fR ?\fIvalue\fR?
.sp
\fIobjectName\fR \fBconfig unset\fR \fIpattern\fR\&.\&.\&.
.sp
\fBexport\fR \fIserial\fR \fIconfiguration\fR
.sp
.BE
.SH DESCRIPTION
This package provides a class to manage the plugins for the export of
keyword indices to other formats, i\&.e\&. their conversion to, for
example \fIdocidx\fR, \fIHTML\fR, etc\&.
.PP
This is one of the three public pillars the management of keyword
indices resides on\&. The other two pillars are
.IP [1]
\fIImporting keyword indices\fR, and
.IP [2]
\fIHolding keyword indices\fR
.PP
.PP
For information about the \fBConcepts\fR of keyword indices, and
their parts, see the same-named section\&.
For information about the data structure which is the major input to
the manager objects provided by this package see the section
\fBKeyword index serialization format\fR\&.
.PP
The plugin system of our class is based on the package
\fBpluginmgr\fR, and configured to look for plugins using
.IP [1]
the environment variable \fBDOCTOOLS_IDX_EXPORT_PLUGINS\fR,
.IP [2]
the environment variable \fBDOCTOOLS_IDX_PLUGINS\fR,
.IP [3]
the environment variable \fBDOCTOOLS_PLUGINS\fR,
.IP [4]
the path "\fI~/\&.doctools/idx/export/plugin\fR"
.IP [5]
the path "\fI~/\&.doctools/idx/plugin\fR"
.IP [6]
the path "\fI~/\&.doctools/plugin\fR"
.IP [7]
the path "\fI~/\&.doctools/idx/export/plugins\fR"
.IP [8]
the path "\fI~/\&.doctools/idx/plugins\fR"
.IP [9]
the path "\fI~/\&.doctools/plugins\fR"
.IP [10]
the registry entry "HKEY_CURRENT_USER\\SOFTWARE\\DOCTOOLS\\IDX\\EXPORT\\PLUGINS"
.IP [11]
the registry entry "HKEY_CURRENT_USER\\SOFTWARE\\DOCTOOLS\\IDX\\PLUGINS"
.IP [12]
the registry entry "HKEY_CURRENT_USER\\SOFTWARE\\DOCTOOLS\\PLUGINS"
.PP
The last three are used only when the package is run on a machine
using Windows(tm) operating system\&.
.PP
The whole system is delivered with six predefined export plugins,
namely
.TP
docidx
See \fIdocidx export plugin\fR for details\&.
.TP
html
See \fIhtml export plugin\fR for details\&.
.TP
json
See \fIjson export plugin\fR for details\&.
.TP
nroff
See \fInroff export plugin\fR for details\&.
.TP
text
See \fItext export plugin\fR for details\&.
.TP
wiki
See \fIwiki export plugin\fR for details\&.
.PP
.PP
Readers wishing to write their own export plugin for some format, i\&.e\&.
\fIplugin writer\fRs reading and understanding the section
containing the \fBExport plugin API v2 reference\fR is an
absolute necessity, as it specifies the interaction between this
package and its plugins in detail\&.
.SH CONCEPTS
.IP [1]
A \fIkeyword index\fR consists of a (possibly empty) set of \fIkeywords\fR\&.
.IP [2]
Each keyword in the set is identified by its name\&.
.IP [3]
Each keyword has a (possibly empty) set of \fIreferences\fR\&.
.IP [4]
A reference can be associated with more than one keyword\&.
.IP [5]
A reference not associated with at least one keyword is not possible
however\&.
.IP [6]
Each reference is identified by its target, specified as either an url
or symbolic filename, depending on the type of reference (\fBurl\fR,
or \fBmanpage\fR)\&.
.IP [7]
The type of a reference (url, or manpage) depends only on the
reference itself, and not the keywords it is associated with\&.
.IP [8]
In addition to a type each reference has a descriptive label as
well\&. This label depends only on the reference itself, and not the
keywords it is associated with\&.
.PP
A few notes
.IP [1]
Manpage references are intended to be used for references to the
documents the index is made for\&. Their target is a symbolic file name
identifying the document, and export plugins may replace symbolic with
actual file names, if specified\&.
.IP [2]
Url references are intended on the othre hand are inteded to be used
for links to anything else, like websites\&. Their target is an url\&.
.IP [3]
While url and manpage references share a namespace for their
identifiers, this should be no problem, given that manpage identifiers
are symbolic filenames and as such they should never look like urls,
the identifiers for url references\&.
.PP
.SH API
.SS "PACKAGE COMMANDS"
.TP
\fB::doctools::idx::export\fR \fIobjectName\fR
This command creates a new export manager object with an associated
Tcl command whose name is \fIobjectName\fR\&. This \fIobject\fR command
is explained in full detail in the sections \fBObject command\fR
and \fBObject methods\fR\&. The object command will be created
under the current namespace if the \fIobjectName\fR is not fully
qualified, and in the specified namespace otherwise\&.
.PP
.SS "OBJECT COMMAND"
All objects created by the \fB::doctools::idx::export\fR command have
the following general form:
.TP
\fBobjectName\fR \fBmethod\fR ?\fIarg arg \&.\&.\&.\fR?
The method \fBmethod\fR and its \fIarg\fR'uments determine the
exact behavior of the command\&.
See section \fBObject methods\fR for the detailed
specifications\&.
.PP
.SS "OBJECT METHODS"
.TP
\fIobjectName\fR \fBdestroy\fR
This method destroys the object it is invoked for\&.
.TP
\fIobjectName\fR \fBexport serial\fR \fIserial\fR ?\fIformat\fR?
This method takes the canonical serialization of a keyword index
stored in \fIserial\fR and converts it to the specified \fIformat\fR,
using the export plugin for the format\&. An error is thrown if no
plugin could be found for the format\&.
The string generated by the conversion process is returned as
the result of this method\&.
.sp
If no format is specified the method defaults to \fBdocidx\fR\&.
.sp
The specification of what a \fIcanonical\fR serialization is can be
found in the section \fBKeyword index serialization format\fR\&.
.sp
The plugin has to conform to the interface specified in section
\fBExport plugin API v2 reference\fR\&.
.TP
\fIobjectName\fR \fBexport object\fR \fIobject\fR ?\fIformat\fR?
This method is a convenient wrapper around the \fBexport serial\fR
method described by the previous item\&.
It expects that \fIobject\fR is an object command supporting a
\fBserialize\fR method returning the canonical serialization of a
keyword index\&. It invokes that method, feeds the result into
\fBexport serial\fR and returns the resulting string as its own
result\&.
.TP
\fIobjectName\fR \fBconfig names\fR
This method returns a list containing the names of all configuration
variables currently known to the object\&.
.TP
\fIobjectName\fR \fBconfig get\fR
This method returns a dictionary containing the names and values of
all configuration variables currently known to the object\&.
.TP
\fIobjectName\fR \fBconfig set\fR \fIname\fR ?\fIvalue\fR?
This method sets the configuration variable \fIname\fR to the
specified \fIvalue\fR and returns the new value of the variable\&.
.sp
If no value is specified it simply returns the current value, without
changing it\&.
.sp
Note that while the user can set the predefined configuration
variables \fBuser\fR and \fBformat\fR doing so will have no
effect, these values will be internally overridden when invoking an
import plugin\&.
.TP
\fIobjectName\fR \fBconfig unset\fR \fIpattern\fR\&.\&.\&.
This method unsets all configuration variables matching the specified
glob \fIpattern\fRs\&. If no pattern is specified it will unset all
currently defined configuration variables\&.
.PP
.SH "EXPORT PLUGIN API V2 REFERENCE"
Plugins are what this package uses to manage the support for any
output format beyond the
\fBKeyword index serialization format\fR\&. Here we specify the
API the objects created by this package use to interact with their
plugins\&.
.PP
A plugin for this package has to follow the rules listed below:
.IP [1]
A plugin is a package\&.
.IP [2]
The name of a plugin package has the form
doctools::idx::export::\fBFOO\fR,
where \fBFOO\fR is the name of the format the plugin will
generate output for\&. This name is also the argument to provide
to the various \fBexport\fR methods of export manager
objects to get a string encoding a keyword index in that
format\&.
.IP [3]
The plugin can expect that the package
\fBdoctools::idx::export::plugin\fR is present, as
indicator that it was invoked from a genuine plugin manager\&.
.IP [4]
A plugin has to provide one command, with the signature shown
below\&.
.RS
.TP
\fBexport\fR \fIserial\fR \fIconfiguration\fR
Whenever an export manager of \fBdoctools::idx\fR has to generate
output for an index it will invoke this command\&.
.RS
.TP
string \fIserial\fR
This argument will contain the \fIcanonical\fR serialization of the
index for which to generate the output\&.
The specification of what a \fIcanonical\fR serialization is can be
found in the section \fBKeyword index serialization format\fR\&.
.TP
dictionary \fIconfiguration\fR
This argument will contain the current configuration to apply to the
generation, as a dictionary mapping from variable names to values\&.
.sp
The following configuration variables have a predefined meaning all
plugins have to obey, although they can ignore this information at
their discretion\&. Any other other configuration variables recognized
by a plugin will be described in the manpage for that plugin\&.
.RS
.TP
user
This variable is expected to contain the name of the user
owning the process invoking the plugin\&.
.TP
format
This variable is expected to contain the name of the
format whose plugin is invoked\&.
.TP
file
This variable, if defined by the user of the index object
is expected to contain the name of the input file for which
the plugin is generating its output for\&.
.TP
map
This variable, if defined by the user of the index object is
expected to contain a dictionary mapping from symbolic file
names used in the references of type \fBmanpage\fR to
actual paths (or urls)\&. A plugin has to be able to handle
the possibility that a symbolic name is without entry in
this mapping\&.
.RE
.RE
.RE
.IP [5]
A single usage cycle of a plugin consists of the invokations of
the command \fBexport\fR\&. This call has to leave the plugin in
a state where another usage cycle can be run without problems\&.
.PP
.SH "KEYWORD INDEX SERIALIZATION FORMAT"
Here we specify the format used by the doctools v2 packages to
serialize keyword indices as immutable values for transport,
comparison, etc\&.
.PP
We distinguish between \fIregular\fR and \fIcanonical\fR
serializations\&. While a keyword index may have more than one regular
serialization only exactly one of them will be \fIcanonical\fR\&.
.PP
.TP
regular serialization
.RS
.IP [1]
An index serialization is a nested Tcl dictionary\&.
.IP [2]
This dictionary holds a single key, \fBdoctools::idx\fR, and its
value\&. This value holds the contents of the index\&.
.IP [3]
The contents of the index are a Tcl dictionary holding the title of
the index, a label, and the keywords and references\&. The relevant keys
and their values are
.RS
.TP
\fBtitle\fR
The value is a string containing the title of the index\&.
.TP
\fBlabel\fR
The value is a string containing a label for the index\&.
.TP
\fBkeywords\fR
The value is a Tcl dictionary, using the keywords known to the index
as keys\&. The associated values are lists containing the identifiers of
the references associated with that particular keyword\&.
.sp
Any reference identifier used in these lists has to exist as a key in
the \fBreferences\fR dictionary, see the next item for its
definition\&.
.TP
\fBreferences\fR
The value is a Tcl dictionary, using the identifiers for the
references known to the index as keys\&. The associated values are
2-element lists containing the type and label of the reference, in
this order\&.
.sp
Any key here has to be associated with at least one keyword,
i\&.e\&. occur in at least one of the reference lists which are the values
in the \fBkeywords\fR dictionary, see previous item for its
definition\&.
.RE
.IP [4]
The \fItype\fR of a reference can be one of two values,
.RS
.TP
\fBmanpage\fR
The identifier of the reference is interpreted as symbolic file name,
referring to one of the documents the index was made for\&.
.TP
\fBurl\fR
The identifier of the reference is interpreted as an url, referring to
some external location, like a website, etc\&.
.RE
.RE
.TP
canonical serialization
The canonical serialization of a keyword index has the format as
specified in the previous item, and then additionally satisfies the
constraints below, which make it unique among all the possible
serializations of the keyword index\&.
.RS
.IP [1]
The keys found in all the nested Tcl dictionaries are sorted in
ascending dictionary order, as generated by Tcl's builtin command
\fBlsort -increasing -dict\fR\&.
.IP [2]
The references listed for each keyword of the index, if any, are
listed in ascending dictionary order of their \fIlabels\fR, as
generated by Tcl's builtin command \fBlsort -increasing -dict\fR\&.
.RE
.PP
.SH "BUGS, IDEAS, FEEDBACK"
This document, and the package it describes, will undoubtedly contain
bugs and other problems\&.
Please report such in the category \fIdoctools\fR of the
\fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&.
Please also report any ideas for enhancements you may have for either
package and/or documentation\&.
.PP
When proposing code changes, please provide \fIunified diffs\fR,
i\&.e the output of \fBdiff -u\fR\&.
.PP
Note further that \fIattachments\fR are strongly preferred over
inlined patches\&. Attachments can be made by going to the \fBEdit\fR
form of the ticket immediately after its creation, and then using the
left-most button in the secondary navigation bar\&.
.SH KEYWORDS
HTML, conversion, docidx, documentation, export, formatting, generation, index, json, keyword index, manpage, markup, nroff, plugin, reference, tcler's wiki, text, url, wiki
.SH CATEGORY
Documentation tools
.SH COPYRIGHT
.nf
Copyright (c) 2009-2019 Andreas Kupries <andreas_kupries@users\&.sourceforge\&.net>

.fi
